To simplify the following discussion, the present invention will be described in terms of an optical communication system in which signals are communicated over fiber optics. However, the monitoring system described herein can be applied to a variety of optical signals.
The ever-increasing bandwidth demands placed on optical networks have led to increased network speeds and wavelength-division multiplexing. These improvements place additional demands on the switching equipment used to route the various optical signals between bands and fibers. This increased complexity, in turn, makes it more difficult to diagnose failures in the various components that make up an optical network or to adjust various compensating devices within the network that correct for the various dispersions introduced by the fibers, amplifiers, and switching equipment.
For example, an optical signal can suffer distortions by being subjected to components that have a gain that varies with the wavelength of the signal. Similarly, the polarization of the signal can be altered in a manner that causes one of the two component linear polarizations to be delayed relative to the other. To correct such distortions, a device that can measure the signal strength, optical phase shift, and polarization of the signal as a function of wavelength is needed.
Broadly, it is the object of the present invention to provide an improved optical monitoring system for measuring multiple parameters in an optical network.
These and other objects of the present invention will become apparent to those skilled in the art from the following detailed description of the invention and the accompanying drawings.